The present invention relates to a composition of lipid molecules and, more particularly, to a self-assembling material composed of lipid molecules induced, via chemical recognition, into a columnar structure with self-limiting dimensions and method of making.
Self-assembling materials are formed from single molecular or ionic components that have complementary interactions (both repulsive and attractive) to bring about the spontaneous formation of ordered supramolecular structures. In particular, liquid crystalline materials produce a myriad of supramolecular structures that can be tailored through their molecular geometry, functionality, and environmental conditions (e.g., salt concentration, temperature, and solvents). Lyotropic liquid crystalline materials, such as the lipid molecules, create vesicular, lamellar, and micellar structures in the aqueous phase (Ringsdorf, H.; Schlarb, B.; Venzmer, J. Angew. Chem. Int. Ed. Engl. 1988, 27, 113). The current and potential uses of such materials include models for cellular membranes and drug delivery vehicles. Block copolymers also can generate unique self-assembled structures in solvents, very similar to lipid molecules. However, their sheer size and chemical complexity can generate new structures and dimensions not previously observed with the lipids. Thermotropic liquid crystalline materials also form highly organized assemblies in two- and three-dimensions, forming discotic, lamellar, hexagonal, and cubic structures.
Although the liquid crystalline materials form highly ordered structures in both two- and three-dimensions, the materials do not exhibit any ability to self-regulate growth. Biological materials show numerous examples of structures that self-regulate growth, such as skeletal systems, tissue, virus particles, among others (Alberts, B.; Bray, D.; Lewis, J.; Raff, M.; Roberts, K.; Watson, J. D. Molecular Biology of The Cell; third ed.; Garland Publishing: New York, 1994). Known systems of lipid bilayer assemblies use ion complexation or molecular recognition at the membrane surface to form supramolecular aggregates with hierarchical structure. Examples include bilayer structures formed through bilayer-DNA (Radler, J. O.; Koltover, I.; Saldift, T.; Safinya, C. R. Science 1997, 275, 810) or bilayer-actin (Wong, G. C. L.; Tang, J. X.; Lin, A.; Li, Y.; Janmey, P. A.; Safinya, C. R. Science 2000, 288, 2035) complexation, metal ion coordination (Constable, E. C.; Meier, W.; Nardin, C.; Mundwiler, S. Chem. Comm. 1999, 1483), or biotin-streptavidin molecular recognition (Chiruvolu, S.; Walker, S.; Israelachvili, J.; Schmitt, F.-J.; Leckband, D.; Zasadzinski, J. A. Science 1994, 264, 1753). In none of these cases do the self-assembled material exhibit any ability to self-limit growth in any dimension.
Self-assembled materials with self-limiting dimensions can have use in a variety of applications for nanotechnology, which include scaffolding for device building, highly oriented structures for light harvesting, nano-scale chemical processing units, and unique drug delivery systems. Such materials are described in Waggoner et al. (Waggoner, T. A.; Last, J. A.; Kotula, P. G.; Sasaki, D. Y. J. Am. Chem. Soc. 2001, 123, 496–497).